JPS6023406B2 - magnetic disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk having a protective coating.

In order to use the space occupied by a magnetic disk as effectively as possible, the best means is to increase the information recording density as much as possible.

However, this requires not only improving the magnetic properties of the magnetic disk, but also reducing the thickness of the magnetic film and minimizing the gap between the magnetic head and the magnetic head, which inevitably increases the number of magnetic heads. It is essential to provide a protective film to protect information on magnetic disks from collisions and wear. Naturally, such a protective film must be extremely thin and have sufficient lubricity or hardness, but there are almost no protective films that meet these conditions, and magnetic disks This is a major obstacle to increasing the density of devices. An object of the present invention is to provide a high-performance magnetic disk that dramatically improves the mechanical durability of conventional magnetic disks.

The structure of the present invention is such that a thin film of graphite-like carbon, a diamond-like carbon thin film, a thin film of graphite-like carbon and a thin film of diamond-like carbon are alternately stacked on the surface of a magnetic disk, or a mixture of graphite-like carbon and diamond-like carbon. The invention is characterized in that it is provided with a protective film made of any of the following thin films.

This invention will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which a is a plan view of a magnetic disk 11 and b is a cross-sectional view XX' thereof. It consists of a magnetic film 13 provided on the surface of a substrate 12 and a film 14 whose main component is carbon, which is provided over almost the entire surface as a protective film. FIG. 2 is a diagram showing another embodiment of the present invention, in which a is a plan view and b is a XX' sectional view.

A magnetic film 23 is provided on the surface of the substrate 22, and a film containing carbon as a main component is provided only in areas of the surface of the magnetic film 23 where collision friction with the magnetic head is likely to occur. Such magnetic disks are particularly effective for recent high-performance magnetic disk drives.

In such a device, the magnetic head is positioned in a specific area on the magnetic disk surface from the stoppage to the initial stage of operation, and the heads are in contact or close to contacting each other.
During normal operation, as the magnetic disk rotates at high speed, the magnetic heads aerodynamically levitate, leaving a small gap, and when they no longer collide with each other, they write and read passion to other areas on the disk surface, that is, the storage area. It should be configured to move. Therefore, by providing the film 24 according to the present invention in such a specific area, it is possible to prevent wear of the disk surface, and also to eliminate the film 24 in the storage area, making it possible to extremely reduce the flying distance between the magnetic film 23 and the magnetic head. The example shown in FIG. 2 is an example of a magnetic disk passed through a device in which the floating state of the magnetic head is extremely stable. FIG. 3 is a diagram showing still another embodiment of the present invention,
A is a plan view, and b is a cross-sectional view taken along the line XX'.

In areas on the magnetic disk surface where collision friction with the magnetic head is likely to occur, there is no magnetic film, and a film 24 whose main component is carbon, which is a feature of the present invention, is provided on the substrate 22. In this embodiment, in addition to the same effects as the embodiment shown in FIG.
Since the level difference on the surface of the magnetic disk can be eliminated to make it a uniform plane, the air flow becomes more uniform, and a magnetic disk device with a more stable floating state can be achieved.

As another embodiment, a structure in which the film, which is a feature of the present invention, is made thicker in areas where collision friction with the magnetic head is likely to occur, and the film is thinner in the storage area, can be mentioned.

Now, in order to make this invention more specific, an example of the method for producing the carbon-based film will be given. Figure 4 schematically shows an example of a device designed for this purpose.
Argon gas is introduced into the ionization chamber 37 from the blower pipe 32 through the needle valve 31, and part of it enters the sample chamber 41 through the vacuum exhaust port 42, the rest passes through the throttle 38, and is exhausted to the outside of the system through the vacuum exhaust port 43. Argon pressure is about 10-2m
The ionization chamber 37, which is maintained at about mHg, has electrodes 34 and 36 having carbon 3 and carbon 35 at their tips, and is powered by a high voltage power supply E (approximately 100 to 1000 volts) under a magnetic field created by a current flowing through an external coil 44. ), a discharge occurs between the carbon electrodes 33 and 35 and carbon atoms or carbon ions are generated. The carbon atoms or carbon ions generated in this way are introduced into a sample chamber 41 drawn to a high vacuum (gas pressure 10-3 to 10-6 mmH Mochiya degree). and forms a film whose main component is carbon. The pressure in the sample chamber 41 is 10-3 to 1
The carbon-based film that forms when the temperature is between 0 and 5 mmHg becomes graphite-like with high lubricity, as reported in the academic journal Journal published in 1971. of. Applied. As reported in JomM1 of Applied Physies, Vol. 42, No. 7, Pages 2953 to 29, the gas pressure in the sample chamber 41 is set to 10-5 to 10-6 mmHg.
It is known that a diamond-like carbon-based film with high hardness can be produced by mounting. The thickness of such a carbon-based film is approximately 500 to 1000 angstroms in the storage area where information is written and transmitted, and 1000 to 100 angstroms in the magnetic head constant pressure section 24 when it is stopped as shown in FIG.
A stroke of approximately 0.00 angstroms is controlled by a predetermined growth time based on the growth rate of the film (approximately several tens to hundreds of angstroms per hour). The structure of the film is not limited to either graphite or diamond-like, but may be a mixture of both or a green layer.By doing so, a protective film with both lubricity and abrasion resistance can be created. Moreover, this can be easily created by controlling the gas pressure inside the sample chamber 41. The above-described embodiments and film production methods are merely examples for embodying the present invention, and magnetic disks may be coated with graphite-like or diamond-like materials containing both carbon as a main component. Needless to say, the features of the present invention can be achieved in both cases.

As explained above, by providing a film mainly composed of carbon on the entire surface or a part of the surface of the magnetic disk,
A magnetic disk that is resistant to wear due to collision with a magnetic head can be achieved.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing embodiments of the present invention.
4 is a plan view, b is a cross-sectional view XX′ thereof, and FIG. 4 is a schematic diagram showing an example of a carbon-based film manufacturing apparatus. 11, 21...magnetic disk, 12, 22...
・Substrate, 13, 23...Magnetic film, 14, 24・
...Carbon-based film, 31...Needle valve, 32...Air pipe, 33,35...
Carbon electrode, 34, 36, 40... Electrode, 37.
...Ionization chamber, 38...Aperture, 39.
...Sample stand, 41...Sample chamber, 42,43...
...Vacuum exhaust port, 44...Coil. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A thin film in which a graphite-like carbon thin film, a diamond-like carbon thin film, and a graphite-like carbon thin film and a diamond-like carbon thin film are alternately stacked on the surface. Alternatively, a magnetic disk characterized in that it is provided with a protective film made of either a thin film containing a mixture of graphite-like carbon and diamond-like carbon. 2. The magnetic disk according to claim 1, wherein a protective film is provided on the entire surface of the magnetic film. 3. The magnetic disk according to claim 1, wherein the protective film is provided only in areas of the surface of the magnetic film where collision friction with the magnetic disk is likely to occur, or is provided thicker than in other areas. 4. A magnetic disk according to claim 1, wherein the protective film is provided in an area where friction with the magnetic head is likely to occur and where there is no magnetic film.